Detergent compositions traditionally contain one or more detergent active material in addition to various other ingredients such as detergency builders, bleaches, fluorescers, perfumes etc. Notable applications of detergent compositions are to clean fabrics, usually by washing portable fabric items in a bowl or in a washing machine, to clean crockery and cooking utensils, again by washing in a bowl (hand dishwashing), and to clean hard surfaces such as glass, glazed surfaces, plastics, metals and enamels.
A number of classes of surfactant materials have been used, some for many years, as detergent active materials, including anionic and nonionic materials.
Glycolipid biosurfactants, which are described in more detail below, include rhamnolipids, sophoroselipids, glucoselipids, cellobioselipids and trehaloselipids. Glycolipid biosurfactants can be produced by either bacterial or yeast fermentation. This is inherently advantageous in that products of fermentation can generally be derived from renewable raw materials and are likely to be biodegradable after use.
JP 63 077 535A (Toyo Beauty) discloses an emulsion composition containing alpha-decenoic bonded rhamnolipid or its salt as emulsifying agent. The emulsion is said to be useful for cosmetics, health-care products, medicines, toiletries, detergents and foods.
DE 3 526 417A (Wella) discloses a cosmetic agent containing sophoroselipid lactone used to combat dandruff and as a bacteriostatic agent in deodorants.
U.S. Pat. No. 4,216,311 (Kao) discloses the production of a glycolipid methyl ester from sophoroselipid. These glycolipid methyl esters are useful as a base or improving additive for various cleansers and fats and oils products and for use in painting and printing processes, fibre processing, metal processing, stationery, cosmetics, drugs, agricultural chemicals, luster prevention, synthetic resins, paper manufacturing, machinery, leather and the like.
Our copending British Patent Application No 91 02945.4 filed 12 Feb. 1991, from which the present application claims priority, describes and claims the use of combinations of rhamnolipids with other surfactants in detergent compositions.
We have now found that glycolipid biosurfactants can give a synergistic enhancement of oily/fatty soil detergency when used in certain combinations with each other, or jointly with other surfactant(s). Enhanced detergency has been observed even with glycolipids that exhibit poor detergency when used alone.